KR20050011832A - Manufacturing method of Holograph film - Google Patents

Abstract

PURPOSE: Provided is a production process of a holograph film which makes ease of minute unevenness patterns with showing excellent solvent resistance and hardness. CONSTITUTION: The production process of the holograph film comprises the steps of: (i) forming UV curable resin layer containing photoinitiator with long wavelength and photoinitiator with short wavelength on a plastic film; (ii) radiating an ultraviolet ray with 250nm or less in wavelength into the ultraviolet hardening resin layer to harden the resin layer partially and form the minute unevenness patterns by embossing processing method; (iii) radiating the ultraviolet ray with 400nm or less in wavelength into the resin layer to harden the resin layer completely; and (iv) vacuum coating metals on the surface of the resin layer.

Description

Manufacturing method of holographic film {Manufacturing method of Holograph film}

The present invention relates to a method for producing a film for holographic (Holograph).

A hologram is a figure representing a stereoscopic image, and an optical recording medium capable of representing a hologram is called a hologram. A hologram is a label (a hologram). It is supplied in the form of a label, a sticker, or a stamping foil, and a unique image of the hologram is widely used as a means of preventing forgery and alteration because it cannot be reproduced by a conventional printing method.

The three-dimensional image of the hologram can be represented by recording the phase information of light on the hologram.

The ability to record a stereoscopic image on a flat hologram forms a fine concavo-convex pattern with different depths and refractive index distribution on the hologram, and the light is generated by the interaction of light having properties such as reflection, absorption, and transmission. To scatter the light, and to cause a relative optical path difference (optical path difference) to the scattered light to be able to feel a three-dimensional feeling.

In general, the holographic film is manufactured in the form of a film. In the conventional holographic film, a thermoplastic resin layer is formed by applying a thermoplastic resin on a synthetic resin film such as polyester terephthalate (hereinafter referred to as PET) resin to form a thermoplastic resin layer. It is produced by forming a fine concavo-convex pattern by embossing method, and vacuum coating the metal thereon. At this time, the fine concave-convex pattern causes the grooves and the projections to be formed on the plane to appear as a fine linear.

Thermoplastic resins used herein include cellulose acetate butylate, cellulose acetate ethylate, urethane resins, etc., and the reason for forming the thermoplastic resin layer is that the thermoplastic resin is relatively soft and has good shape retention. This is because it is easy to form a fine concave-convex pattern. In addition, when the vacuum deposition of the metal will be well reflected and scattered light.

However, the thermoplastic resin layer formed on the surface of the synthetic resin film has low hardness, heat resistance, and solvent resistance, and thus is easily damaged by an external impact. If this is damaged, it is not possible to display an accurate image.

Therefore, in this field, there is a demand for the development of a holographic film composed of a material which is excellent in hardness and solvent resistance and can easily form fine rough patterns.

SUMMARY OF THE INVENTION An object of the present invention is to provide a holographic film having excellent hardness and solvent resistance while being easy to form an uneven pattern showing a hologram.

The present inventors form an ultraviolet curable resin layer containing both a short wavelength photoinitiator and a long wavelength photoinitiator on one surface of a synthetic resin film such as a PET resin film, and then irradiate the short wavelength ultraviolet rays to make the ultraviolet resin layer semi-cured and the resin layer In the semi-cured state, by forming the fine iron pattern on it by embossing method, and irradiating the ultraviolet rays of the long wavelength and completely hardening it, and depositing the metal, it is easy to form the fine iron pattern. The present invention was completed by confirming that a film for use could be obtained.

The present invention relates to a method for producing a holographic film having excellent solvent resistance and surface hardness while being able to easily form a fine concave-convex pattern showing a hologram.

A feature of the present invention is that in the holographic film, the micro-convex pattern layer formed on the plastic film is formed of an ultraviolet curable resin containing both a short wavelength photoinitiator and a long wavelength photoinitiator, and irradiated with short wavelength ultraviolet rays to the resin layer, and the resin layer. After forming a fine concave pattern by the embossing method in a semi-cured state, and irradiated with long-wave ultraviolet rays, the UV curable resin layer is completely cured and a metal deposition layer is formed thereon. will be.

The present invention will be described in detail with reference to the following Examples.

Example 1

<Production of UV Curing Resin>

UV curable resins generally consist of low molecular weight polymers (oligomers) and monomers (monomers), solvent-soluble resins, photoinitiators and organic solvents with few repeating units. Here, the photoinitiator refers to a material that acts as a polymerization initiator by UV irradiation, the organic solvent refers to a solvent such as methyl ethyl ketone or toluene, and the organic solvent soluble resin refers to a resin that is well soluble in the organic solvent.

In the present invention, a short wavelength photoinitiator is mixed with a long wavelength photoinitiator. Here, the short wavelength photoinitiator refers to a photoinitiator that is sensitive to ultraviolet rays having a wavelength of 250 nm or less, and the long wavelength photoinitiator refers to a photoinitiator that is sensitive to ultraviolet rays of 400 nm or less.

The oligomers that can be used in the present invention include epoxy acrylate, urethane acrylate, polyester acrylate, acryl acrylate, amine-modified acrylate, urethane methacrylate, and the like, and these may be used alone or in combination.

The monomers include lauryl acrylate, isobornyl acrylate, isodecyl acrylate, styryl acrylate, 1.6 hexanediol diacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, pentaerythritol tetraacrylate, Trimethylol propane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol penta acrylate, dipentaerythritol nucleoacrylate and the like alone or mixed Can be used.

The short wavelength photoinitiator includes diphenyl ketone benzyl dimethyl ketal, 2-hydroxy-2-methyl-1-phenyl-1-one and 4-hydroxy cyclophenyl ketone, and the long wavelength photoinitiator is 2.4.6-trimethyl benzoyl diphenylphosphine. Oxide, 2-methyl-1- (4-methylthio) -phenyl-2-morpholinopuropan-2-one, 2-bis (2.6-dimethoxybenzoyl) -2.4.4-trimethyl phosphineoxide, 2.4 -Diethylthio oxanthone, 4-dimethyl amino benzoic acid ethyl ester, 2-isofurophyl thiooxanthone, 4-isofurophyl thiooxanthone, etc. are mentioned.

Organic solvent soluble resins include rosin ester resin, petroleum resin, styrene-isoprene-styrene resin, nitro cellulose, ethyl cellulose acetate, butyl cellulose acetate, acrylic resin urethane acrylate, epoxy acrylate, ethylene vinyl acetate, coumarone indene resin, etc. This can be used. As the organic solvent, methyl ethyl ketone (MEK) or toluene is used, and a mixed solvent obtained by mixing them by 50% by weight is most suitable.

UV curable resin compositions to be used in the following Examples were prepared according to the compositions shown in Table 1 below.

TABLE 1

Composition example of composition for manufacturing ultraviolet curing resin

Unit: parts by weight Example 1 Example 2 Epoxyacrylate (Oligomer) 31 - Urethane Acrylate (Oligomer) - 31 Methyl ethyl ketone 50wt + toluene 50wt% (solvent) 50 50 Trimethylolpropane triacrylate (monomer) 10 10 Cellulose resin (solvent soluble resin) 5 5 2-isophorophylliooxane (long wavelength photoinitiator) One One 4-hydroxycyclophenyl ketone (short wavelength photoinitiator) 3 3

<Production of holographic film>

Example 1

On the surface of PET film having a thickness of 40 μm, the ultraviolet curable resin composition having the composition described in Example 1 was applied by a gravure printing method so that the thickness of the dry coating film was 5 μm.

It is dried by hot air for about 30 seconds while moving at a speed of 60 m / min in a drying chamber at 100 ° C.

When the ultraviolet rays are irradiated with ultraviolet light having a wavelength of 250 nm, the ultraviolet curable resin layer is not cured completely but remains in a semi-cured state.

In order to maintain the semi-cured state without completely curing the UV curable resin, the wavelength of the irradiated short wavelength ultraviolet ray should be 250 nm or less, and 50 ~ 250 nm is appropriate.

After forming a micro-corrugated pattern that shows a hologram by embossing method and irradiating long wavelength ultraviolet rays with a wavelength of 400 nm or less, the ultraviolet curable resin is completely cured.

In order to completely cure the UV-curing resin, the wavelength of the long-wavelength ultraviolet ray to be irradiated should be 400 nm or less, and 250 to 400 nm is appropriate.

When the ultraviolet curable resin is completely cured, metal vacuum deposition on the surface thereof yields the holographic film of the present invention.

Vacuum deposition on the film surface is well known in the art, and a film made of nylon resin or polycarbonate resin may be used instead of PET film.

Example 2

A holographic film was prepared in the same manner as in Example 1, except that the ultraviolet curable resin composition was used in Example 2 of Table 1 above, and the surface hardness, solvent resistance, and the like of the film were tested and the results were obtained. The following [Table 2] is shown.

[Table 2] Physical property test table of holographic film

Example 1 Example 2 Surface hardness (pencil hardness) 5H 4H Adhesion to Evaporation Surface 100/100 100/100 Solvent resistance clear clear Emmosing workability Great Great ※ ㆍ Adhesion test on the deposition surface: 100 100 indicates the state that all 100 specimens were kept in adhesion. Solvent resistance: Determination of abnormality after immersion in methyl ethyl ketone solvent 50 times. Embossing workability: Unevenness The degree of uneven pattern formation was evaluated by testing the degree of pattern formation.

In the state of the UV-curable resin layer of the holographic film produced by the method of the present invention is not completely cured, by forming a fine rough pattern to make the hologram appear here, it is easy to form a fine rough pattern, After hardening, it is completely hardened, so the surface hardness and solvent resistance are excellent, and the possibility of damage by external shock is greatly reduced.

The method of the present invention has an effect of providing a holographic film having excellent hardness and solvent resistance while being easy to form a fine concave-convex pattern that shows a hologram.

Claims (2)

In the method of manufacturing a holographic film, an ultraviolet curable resin layer containing both a long wavelength light initiator and a short wavelength light initiator is formed on a plastic film, and the ultraviolet curable resin layer is semi-cured by irradiating ultraviolet rays having a wavelength of 250 nm or less. A method of manufacturing a holographic film for forming a fine convex pattern by an embossing method in a state and then irradiating ultraviolet rays having a wavelength of 400 nm or less to completely cure the ultraviolet curable resin layer, and vacuum depositing metal vacuum on the surface of the ultraviolet curable resin layer. The method of claim 1, wherein the plastic film is a film of polyester resin, nylon resin or polycarbonate resin, the short wavelength photoinitiator is diphenyl ketone benzyl dimethyl ketal, 2-hydroxy-2-methyl-1-phenyl-1-one Or 4-hydroxy cyclophenyl ketone, wherein the long wavelength photoinitiator is 2.4.6-trimethylmethyl benzoyl diphenyl phosphine oxide, 2-1-methyl-1- (4-methylthio) -phenyl-2-polynofuro A method for producing a holographic film, which is selected from pan-2-one or 2-bis (2.6-dimethoxybenzoyl) -2.4.4-trimethyl poxpin oxide.